"parasitism, relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing it. Parasitism is differentiated from parasitoidism, a relationship in which the host is always killed by the parasite; parasitoidism occurs in some Hymenoptera (ants, wasps, and bees), Diptera (flies), and a few Lepidoptera (butterflies and moths): the female lays her eggs in or on the host, upon which the larvae feed on hatching."
"parasitism, relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing it. Parasitism is differentiated from parasitoidism, a relationship in which the host is always killed by the parasite; parasitoidism occurs in some Hymenoptera (ants, wasps, and bees), Diptera (flies), and a few Lepidoptera (butterflies and moths): the female lays her eggs in or on the host, upon which the larvae feed on hatching."
http://www.britannica.com/EBchecked/topic/443191/parasitism